Indoor nitrogen dioxide levels fell 70% after stove change
More than one-third of American households rely on natural gas stoves, but burning natural gas generates nitrogen dioxide and other compounds that can irritate the lungs, according to researchers who conducted the study. An analysis of more than 40 studies found a correlation between nitrogen dioxide levels and asthma symptoms. The 28 million Americans with asthma may be especially susceptible, the researchers said.
Dr. Ashwini Sehgal, a professor of medicine at Case Western Reserve University, said the study was the first to examine whether replacing gas stoves with electric stoves can improve asthma symptoms.
Contractors removed the gas stoves from participants’ homes, safely capped gas lines, installed necessary electrical outlets and replaced the stoves with electric induction models at no cost to participants. The research team assessed asthma control based on a standard questionnaire participants filled out before the stove replacement and again two to three months afterward, and used air quality monitors to measure indoor nitrogen dioxide levels for seven-day periods before and after the change.
“The results were striking: Improvements in asthma symptoms following stove change were similar to — or even greater than — those reported in clinical trials of commonly used asthma medications,” Sehgal said.
On average, participants went from having moderate asthma symptoms to having mild symptoms. Emergency room visits and hospitalizations for asthma fell by 70%, according to the researchers. Missed days of work or school because of asthma dropped by about 80%. Indoor levels of nitrogen dioxide decreased by 70%.
Sehgal noted that the study included a relatively small number of participants and followed them for only a few months, and that the findings may not apply to people with milder asthma. The study also did not include a comparison group that kept their gas stoves.
The cost of replacing gas stoves is likely to be a barrier for low-income communities, Sehgal said. In newer American homes, an electric stove and its installation typically costs about $1,500. Most study participants lived in homes built before 1960, and the research team spent an average of $7,000 per household to upgrade their electrical systems.
“These findings suggest that a relatively simple change in the home — switching from a gas stove to an electric stove — may lead to meaningful improvements in asthma control for people who are struggling with their symptoms,” Sehgal said.
Sehgal said that given the potential cost savings from reduced emergency room visits and hospitalizations, it might make sense for governments or health insurers to subsidize the costs of replacing gas stoves with electric ones for patients with poorly controlled asthma. He pointed to a program in Ecuador where the government subsidized 750,000 households — one-tenth of all households in the country — to replace gas stoves with electric induction stoves from 2015 to 2021. Program uptake correlated with declines in hospitalizations for respiratory illnesses.
Switching stoves is not a cure for asthma and may not help everyone, Sehgal said, adding that about 80% of study participants experienced meaningful improvements. People with asthma should continue working with their physicians, taking prescribed medications and reducing exposure to other asthma triggers, such as cigarette smoke, dust mites, pollen and viral respiratory infections, he said.